Johnson Creek, Portland, Oregon

Portland, Oregon, is attracting interest from UK research programmes as an aspirational template for beneficial ‘blue-green’ built environment. However, upstream of Portland, . . . .

” . . . seven major floods occurred on Johnson Creek in the last 35 years, and 28 since 1941. It was both flooding and water quality issues that put Johnson Creek basin on the top of the City’s priority list. Located on the southeast side of Portland and on the eastern side of the Willamette River basin, Johnson Creek flows 26 miles west through six different jurisdictions and finally into the Willamette River. Although just a small portion (6 %) of Portland’s “100 year” floodplain is in the Johnson Creek watershed, it accounts for the majority (78%) of Portland’s repetitive flood loss claims.”

The opportunity may exist to diffuse, in rural upstream reaches, the peaks of floods which will fill urban green-space and cause downstream loss. An indicative model could provide useful evidence for research teams.